High-speed absolute femtosecond laser ranging device

Abstract

The application discloses a high-speed absolute femtosecond laser ranging device, which comprises a fine measurement light source system, a coarse measurement laser light source, a coarse-fine fusion ranging system and a measurement signal detection and processing module. The fine measurement light source system is used for outputting a sampling clock signal and a frequency-locked femtosecond laser fine measurement signal. The coarse measurement laser light source is used for outputting a coarse measurement laser signal. The wavelength of the femtosecond laser fine measurement signal is different from that of the coarse measurement laser signal. The coarse-fine fusion ranging system is used for measuring a measured target by using the femtosecond laser fine measurement signal and the coarse measurement laser signal, and obtaining a reference light signal, a measurement light signal and a coarse measurement light signal. The measurement signal detection and processing module is used for performing coarse measurement and fine measurement calculation on the reference light signal, the measurement light signal and the coarse measurement light signal to obtain a ranging result. Therefore, the application can be used for high-speed motion target real-time positioning, aerospace detection and other scenes.

Description

Technical Field

[0001] This invention relates to the field of optical precision metrology, specifically to a high-speed absolute femtosecond laser ranging device. Background Technology

[0002] The high-speed absolute femtosecond laser ranging device aims to solve the problems of traditional TOF ranging systems being limited by device specifications, optical frequency comb optical asynchronous sampling (OAS) technology being unable to achieve ultra-high dynamic ranging capabilities, and having high requirements for reflected light intensity and being difficult to implement in engineering.

[0003] The principle of high-velocity absolute femtosecond laser ranging devices is to generate signal light pulses with a stable time reference through a repetition-rate locked femtosecond light source. The probe laser pulse is emitted to the target, and the echo laser pulse reflected by the target object is received and converted into an electrical signal. The electrical signal is then asynchronously sampled to obtain sampling data. Based on the time reference of the optical frequency comb and the timing relationship of the electrical asynchronous sampling, the flight time of the echo laser pulse is reconstructed, and then the absolute distance of the target object is calculated. The above measurement does not rely on interferometric optical paths and high-bandwidth hardware. It combines the high-precision time reference advantage of the optical frequency comb with the engineering feasibility of electrical asynchronous sampling, improves the data utilization rate of the measurement signal, and realizes accurate and fast distance reconstruction. However, the non-ambiguity range of the pulse ranging of the above measurement device is limited, and it cannot achieve high-precision absolute distance measurement within a kilometer-level non-ambiguity range. Summary of the Invention

[0004] The present invention aims to at least solve one of the technical problems existing in the prior art. Therefore, in response to the above-mentioned problems, the object of the present invention is to provide a high-velocity absolute femtosecond laser ranging device capable of achieving high-precision absolute distance measurement within a kilometer-level unambiguous range.

[0005] To achieve the aforementioned objectives, the technical solution adopted by this invention is as follows: This invention provides a high-velocity absolute femtosecond laser ranging device, which includes a fine measurement light source system, a coarse measurement laser light source, a coarse-fine fusion ranging system, and a measurement signal detection and processing module.

[0006] The precision measurement light source system is used to output a sampling clock signal and a repetition rate locked femtosecond laser precision measurement signal;

[0007] The coarse measurement laser source is used to output a coarse measurement laser signal, wherein the femtosecond laser fine measurement signal and the coarse measurement laser signal have different wavelengths;

[0008] The coarse-fine fusion ranging system is used to measure the target under test by combining the femtosecond laser fine measurement signal and the coarse measurement laser signal to obtain the reference optical signal, the measurement optical signal and the coarse measurement optical signal;

[0009] The measurement signal detection and processing module is used to perform coarse and fine measurement calculations on the reference optical signal, measurement optical signal and coarse measurement optical signal to obtain the ranging result.

[0010] In some possible implementations, the precision measurement light source system includes a time and frequency reference module, a signal generation module, and a femtosecond laser light source, wherein:

[0011] The time and frequency reference module is used to provide a standard frequency reference signal;

[0012] The signal generation module outputs two standard frequency signals based on the standard frequency reference signal provided by the time-frequency reference module: one input is the repetition rate locking reference signal provided by the femtosecond laser source, and the other input is the frequency provided by the measurement signal detection and processing module. f s The sampling clock signal,

[0013] The femtosecond laser source is used to emit a femtosecond laser precision measurement signal with repetition rate lock.

[0014] In some possible implementations, the coarse-fine fusion ranging optical path includes an optical fiber interferometer and a collimator, wherein:

[0015] The fiber optic interferometric optical path is used to perform signal measurement on the target under test based on fiber optic transmission, and to obtain a reference optical signal, a measurement optical signal and a coarse measurement optical signal.

[0016] The fiber collimator is positioned between the exit of the fiber interference optical path and the target under test. It is used to convert the divergent light output from the fiber into parallel light, and also to couple the parallel light reflected by the target under test into the fiber.

[0017] In some possible implementations, the fiber optic interference path includes a filter, a coupler, a first circulator, a second circulator, and a wavelength division multiplexer, wherein:

[0018] The femtosecond laser precision measurement signal is split into two paths after passing through the filter and coupler: one path is used as a reference light and directly input to the measurement signal detection and processing module; the other path is used as the measurement light, which passes through the first circulator and wavelength division multiplexer, and is converted into spatial collimated light by the fiber collimator and incident on the target under test. After returning along the original path, it passes through the wavelength division multiplexer and the first circulator in sequence to obtain the measurement light signal, which is then transmitted to the measurement signal detection and processing module.

[0019] The coarse measurement laser source passes through the second circulator, is input to the wavelength division multiplexer and the measurement optical signal, and is then combined and incident on the target under test through the fiber collimator. After that, it returns to the second circulator along the original path to obtain the coarse measurement optical signal, which is then transmitted to the measurement signal detection and processing module.

[0020] In some possible implementations, the center wavelength of the filter is substantially the same as the center wavelength of the femtosecond laser source, and the bandwidth range of the filter does not overlap with the bandwidth range of the coarse-measured laser source.

[0021] In some possible implementations, the measurement signal detection and processing module includes first to third photodetectors, a high-speed signal acquisition circuit, and a signal processing circuit, wherein:

[0022] The first to third photodetectors are used to receive the reference optical signal, the measurement optical signal and the coarse measurement optical signal output from the coarse and fine fusion ranging optical path, respectively, and convert them into corresponding electrical signals.

[0023] The high-speed signal acquisition circuit is used to acquire clock signals. f s Let be the sampling frequency, and be the repetition frequency. The reference electrical signal and the measured electrical signal are sampled to generate a reference electrical pulse signal and a measured electrical pulse signal;

[0024] The signal processing circuit is used to process the coarse measurement signal to obtain the coarse measurement result, process the reference electrical pulse signal and the measurement electrical pulse signal, and fuse the coarse measurement result to obtain the ranging result.

[0025] In some possible implementations, the coarse measurement laser source is a nanosecond laser, used to achieve low-precision measurement of the target based on the TOF method.

[0026] In some possible implementations, the ranging results for:

[0027] ;

[0028] in, The group velocity of the light pulse in the air. For time delay, For the repetition rate of the femtosecond laser precision measurement signal, sampling frequency Repetition frequency of femtosecond laser precision measurement signal The frequency difference The period is an integer multiple of the non-fuzzy range.

[0029] In some possible implementations, the period is an integer multiple of the non-fuzzy range. The calculation formula is:

[0030] ;

[0031] In the formula, INT stands for floor function. This is a rough distance measurement.

[0032] In some possible implementations, coarse distance measurement The calculation formula is:

[0033] ;

[0034] in, c At the speed of light, To roughly measure the time difference from laser emission to reception.

[0035] Because the present invention adopts the above technical solution, it has the following characteristics:

[0036] 1. This invention includes a compact femtosecond laser source, a coarse-fine fusion ranging optical path, and a measurement signal acquisition and processing module. Compared with the prior art, it adds a coarse ranging optical path, and for the first time proposes an all-fiber form for the fine ranging optical path, which improves the integration of the fine ranging optical path. It also proposes an integrated coarse-fine fusion optical path. The device expands the unambiguous range to the unambiguous range of the coarse ranging module through coarse-fine fusion ranging, which is generally at the kilometer level. Therefore, it can realize absolute distance measurement with a large unambiguous range, high precision, and high measurement speed, and expand the unambiguous range of electrical pulse ranging.

[0037] 2. The coarse-fine fusion large unambiguous absolute ranging method provided by the present invention uses electrical pulse as fine measurement and nanosecond pulse time-of-flight ranging as coarse measurement, which extends the unambiguous range of electrical pulse ranging from the meter level to the kilometer level. Through real-time data fusion ranging, high-precision absolute distance measurement within the kilometer-level unambiguous range can be achieved, and the measurement frequency can reach the megahertz level.

[0038] In summary, this invention can be applied to scenarios such as real-time positioning of high-speed moving targets and aerospace inspection. Attached Figure Description

[0039] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts. In the drawings:

[0040] Figure 1 This is a schematic diagram of the high-velocity absolute femtosecond laser ranging device according to an embodiment of the present invention;

[0041] Figure 2 This is a schematic diagram of the coarse-fine fusion ranging optical path according to an embodiment of the present invention;

[0042] Figure 3 This is a schematic diagram of the measurement signal detection and processing module according to an embodiment of the present invention. Detailed Implementation

[0043] It should be understood that the terminology used herein is for the purpose of describing particular exemplary embodiments only and is not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms “a,” “an,” and “described” as used herein may also include the plural forms. The terms “comprising,” “including,” “containing,” and “having” are inclusive and therefore indicate the presence of the stated features, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, elements, components, and / or combinations thereof. The method steps, processes, and operations described herein are not construed as requiring them to be performed in a particular order described or illustrated unless the order of performance is explicitly indicated. It should also be understood that additional or alternative steps may be used.

[0044] Although terms such as first, second, third, etc., may be used in this document to describe multiple elements, components, regions, layers, and / or segments, these elements, components, regions, layers, and / or segments should not be limited by these terms. These terms may be used only to distinguish one element, component, region, layer, or segment from another. Unless the context clearly indicates otherwise, terms such as "first," "second," and other numerical terms used herein do not imply order or sequence. Therefore, the first element, component, region, layer, or segment discussed below may be referred to as the second element, component, region, layer, or segment without departing from the teachings of the exemplary embodiments.

[0045] For ease of description, spatial relative terms may be used in the text to describe the relationship of one element or feature relative to another element or feature as shown in the figure. These relative terms include, for example, "inside," "outside," "middle," "outer," "below," "above," etc. Such spatial relative terms are intended to include different orientations of the device in use or operation, other than those depicted in the figure.

[0046] Existing pulse ranging devices have limited unambiguous range, making it impossible to achieve high-precision absolute distance measurement within a kilometer-level unambiguous range. This invention provides a high-velocity absolute femtosecond laser ranging device, comprising a precision light source system, a coarse laser light source, a coarse-precision fusion ranging system, and a measurement signal detection and processing module. The precision light source system outputs a sampling clock signal and a repetition-locked femtosecond laser precision measurement signal; the coarse laser light source outputs a coarse laser signal, wherein the femtosecond laser precision measurement signal and the coarse laser signal have different wavelengths; the coarse-precision fusion ranging system measures the target using the femtosecond laser precision measurement signal and the coarse laser signal, acquiring a reference light signal, a measurement light signal, and a coarse light signal; the measurement signal detection and processing module performs coarse and fine measurement calculations on the reference light signal, the measurement light signal, and the coarse light signal to obtain the ranging result. Therefore, this invention, through real-time data fusion ranging, can achieve high-precision absolute distance measurement within a kilometer-level unambiguous range, with a measurement frequency reaching the megahertz level.

[0047] Exemplary embodiments of the invention will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the invention are shown in the drawings, it should be understood that the invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the invention and to fully convey the scope of the invention to those skilled in the art.

[0048] like Figure 1 As shown, the high-velocity absolute femtosecond laser ranging device provided in this embodiment includes a fine measurement light source system 1, a coarse measurement laser light source 2, a coarse-fine fusion ranging system 3, and a measurement signal detection and processing module 4.

[0049] The precision measurement light source system 1 is used to output the sampling clock signal and the repetition rate locked femtosecond laser precision measurement signal;

[0050] Coarse measurement laser source 2 is used to output coarse measurement laser signal, wherein the wavelength of the femtosecond laser fine measurement signal and the coarse measurement laser signal are different;

[0051] The coarse-fine fusion ranging system 3 is used to measure the target by combining the femtosecond laser fine measurement signal and the coarse measurement laser signal to obtain the reference optical signal, the measurement optical signal and the coarse measurement optical signal;

[0052] The measurement signal detection and processing module 4 is used to calculate the ranging signal based on the reference optical signal, the measurement optical signal and the coarse measurement optical signal to obtain the ranging result.

[0053] In a preferred embodiment of the present invention, the coarse measurement laser source 2 can be a nanosecond laser, used to achieve low-precision measurement of the target distance based on the TOF method.

[0054] In a preferred embodiment of the present invention, the precision measurement light source system 1 includes a time and frequency reference module 11, a signal generation module 12, and a repetition rate locked femtosecond laser light source 13, wherein:

[0055] The time and frequency reference module 11 is used to provide a standard frequency reference signal to ensure the accuracy of the standard frequency signal output by the signal generation module 12.

[0056] Signal generation module 12 is used to output two standard frequency signals: one to provide a repetition frequency of 13 to the repetition-rate locked femtosecond laser source 13. f r or f r The reference signal, with a repetition frequency that is an integer multiple, is used to lock onto the signal, and one path provides the measurement signal detection and processing module 4 with a frequency of... f s The sampling clock signal, wherein the repetition frequency of the femtosecond laser source 13 is... f r Typically, the frequency ranges from tens of megahertz to hundreds of megahertz. f s and f r The frequency difference is typically between hundreds of kilohertz and megahertz.

[0057] The femtosecond laser source 13 is used to emit a repetition rate locked femtosecond laser as a femtosecond laser precision measurement signal.

[0058] In a preferred embodiment of the present invention, such as Figure 2 As shown, the coarse-fine fusion ranging optical path 3 includes an optical fiber interferometric optical path 31 and a collimator 32. It combines the femtosecond laser fine measurement signal and the coarse measurement laser through an optical fiber, and forms a collimated spatial light output through the collimator 32. It also receives the reflected light from the target 5, forming a reference light signal, a measurement light signal, and a coarse measurement light signal in the optical fiber interferometric optical path. These signals are then input to the measurement signal detection and processing module 4. Wherein:

[0059] The fiber optic interferometric optical path 31 measures the target 5 based on fiber optic transmission, and obtains a reference optical signal, a measurement optical signal, and a coarse measurement optical signal.

[0060] The fiber collimator 32 is positioned between the fiber outlet of the fiber interference optical path 31 and the target 5 under test. It is used to convert the divergent light output from the fiber into parallel light, and also to efficiently couple the parallel light reflected by the target 5 under test into the fiber.

[0061] Furthermore, the fiber optic interferometric optical path 31 includes a filter 311, a coupler 312, a first circulator 313, a second circulator 314, and a wavelength division multiplexer 315. The precision measurement signal light emitted by the frequency-repetition-locked femtosecond laser source 13 is split into two paths after passing through the filter 311 and the coupler 312: the reference light is directly input into the first photodetector 41 of the measurement signal detection and processing module 4, and the measurement light is input into the fiber optic collimator 32 after passing through the first circulator 313 and the wavelength division multiplexer 315. It is then converted into spatially collimated light and incident on the target 5. After returning along the original path, it passes through the wavelength division multiplexer 315 and the first circulator 313 in sequence to obtain the measurement light signal. The measurement light signal is then transmitted to the second photodetector 42 of the measurement signal detection and processing module 4. The coarse measurement laser source 2 passes through the second circulator 314 and is input into the wavelength division multiplexer 315. After being combined with the measurement light, it is emitted to the target under test 5. Similarly, it returns along the original path to the second circulator 314 and outputs the coarse measurement light signal, which is then emitted to the third photodetector 43 of the measurement signal detection and processing module 4.

[0062] Furthermore, since the signal light is a wide-spectrum femtosecond laser source 13, in order to avoid crosstalk between coarse and fine measurement light, the center wavelength of filter 311 is required to be basically the same as the center wavelength of femtosecond laser source 13, and the bandwidth range of filter 311 does not overlap with the bandwidth range of coarse measurement laser source 2.

[0063] Furthermore, the first circulator 313 and the second circulator 314 are used to realize unidirectional ring transmission of optical signals, enabling light to be transmitted from port 1 to port 2 to port 3 with extremely high reverse isolation.

[0064] Furthermore, the wavelength division multiplexer 315 is used to realize the multiplexing and demultiplexing of the coarse optical signal and the fine optical signal. The two inputs of the wavelength division multiplexer 315 can be matched with the spectral bandwidth of the filter 311 and the coarse optical laser source 2.

[0065] In a preferred embodiment of the present invention, such as Figure 3 As shown, the measurement signal detection and processing module 4 includes first to third photodetectors 41 to 43, a high-speed signal acquisition circuit 44, and a signal processing circuit 45. It is used to convert optical signals to electrical signals, acquire signals, and calculate ranging signals. It transmits the fused measurement results of coarse and fine measurements to the host computer 6.

[0066] The first to third photodetectors 41 to 43 respectively receive the reference optical signal, the measurement optical signal, and the coarse measurement optical signal output from the coarse-fine fusion ranging optical path, and convert them into corresponding electrical signals. The detection bandwidth of the three photodetectors is generally greater than 2. .

[0067] High-speed signal acquisition circuit 44, using clock signal Let be the sampling frequency, and be the repetition frequency. The reference electrical signal and the measurement electrical signal are sampled to generate a reference electrical pulse signal and a measurement electrical pulse signal, which are then input to the signal processing circuit 45 for real-time distance calculation. The sampling rate of the high-speed signal acquisition circuit 44 is not strictly required, but it must satisfy the Nyquist sampling theorem.

[0068] The signal processing circuit 45 is used to process the reference electrical pulse signal and the measurement electrical pulse signal to obtain the fine measurement result, and to process the coarse measurement signal to obtain the coarse measurement result. At the same time, the coarse measurement result and the fine measurement result are fused to obtain the final ranging result, and the final result is output to the host computer 6.

[0069] In a preferred embodiment of the present invention, the target 5 is used to reflect the measurement signal. This is not limited to any particular target, and can be a corner cube prism or other non-cooperative target.

[0070] The measurement principle of the high-velocity absolute femtosecond laser ranging device of the present invention will be described in detail below.

[0071] Coarse ranging employs time-of-flight ranging technology. Its principle is to use a pulsed laser with a repetition frequency in the kilohertz range and a pulse width in the nanosecond range as the light source. The echo signal from the third photodetector 43 is used to calculate the time of flight of the pulse in space, that is, the time difference from the emission of the nanosecond laser to its reception by the third photodetector 43. Perform distance measurement on the target object, and perform a coarse distance measurement. It can be represented as:

[0072] (1);

[0073] in, It's the speed of light.

[0074] It should be noted that due to the periodicity of the femtosecond laser source pulses, the ranging device exhibits a non-ambiguous distance. If the time delay between the measured signal and the reference signal is greater than one period, i.e., the measured distance is greater than the unambiguous distance, the fine ranging result cannot distinguish periods that are integer multiples of the unambiguous range. N .

[0075] By rough distance measurement The period of integer multiples of the non-fuzzy range can be directly calculated. N :

[0076] (2);

[0077] In the formula, INT represents the floor sign, which is used when the coarse measurement accuracy is better than... hour ， This can uniquely determine N value.

[0078] Precise ranging uses the principle of electrical pulse ranging and sets the sampling frequency. repetition rate with femtosecond laser source Maintain a certain frequency difference The electrical pulses output by the first photodetector 41 and the second photodetector 42 are transmitted by the high-speed signal acquisition circuit 44. The sampling rate is acquired asynchronously, and high-repetition-frequency electrical pulses are asynchronously reconstructed. This asynchronous sampling method amplifies the time-domain scale of the electrical pulses. / Times, that is, at every T=1 / During the measurement period, a reference signal and a measurement signal will appear. This invention uses a coarse-fine fusion ranging method to obtain the ranging result of the measured target. D TOF Time delay between reference signal and measurement signal The calculation yielded:

[0079] (3);

[0080] in, It is the group velocity of the light pulse in the air, with respect to time delay. The positioning is not limited, but the centroid method is preferred for implementation:

[0081] Assume the voltage amplitudes at each point of the reconstructed electrical pulse recorded by asynchronous sampling are as follows: U 1. U 2. U 3… U n ,use t 1. t 2. t 3…… t n The x-coordinate represents the position of each point, which is the sampling order. Because the sampling clock is strictly locked, the x-coordinate corresponds to the sampling time. The calculation formula for the pulse centroid method is as follows:

[0082] (4);

[0083] in, The average time after weighting the pulse signals is represented by the time points of the two sets of electrical pulse waveforms. and The time of flight of the femtosecond laser pulse during the detection of the target can be obtained by subtracting the time of flight. = - .

[0084] For example, for repetition frequency An optical frequency comb of approximately 100MHz can measure the difference between the sampling frequency and the signal repetition frequency. Setting the frequency to around 1MHz allows for ultra-high-speed absolute distance measurement with a kilometer-level unambiguous range and a precision down to the hundreds of micrometers. It's important to note that the repetition rate of coarse laser measurements is typically in the kHz range, corresponding to the measurement frequency... Typically in kHz, precision laser measurement frequency. Typically in the MHz range, because the accuracy requirement for coarse-fine fusion is only that the coarse measurement accuracy is better than... hour ， This can uniquely determine N For a femtosecond laser source with a repetition rate of 100MHz, the coarse measurement accuracy requirement is only 0.75m. In most dynamic scenarios, the moving target is unlikely to move more than 0.75m within the kHz coarse measurement interval (i.e., sub-millimeter interval). Therefore, during data fusion, the fine measurement laser signal can be output at the kHz level and synchronized with the fine measurement results. / The fine measurement data can be fused using the same coarse measurement result.

[0085] In summary, this invention expands the unambiguous range to the coarse unambiguous range, typically at the kilometer level, through coarse-fine fusion ranging, thus enabling absolute distance measurement with a large unambiguous range, high precision, and high measurement speed.

[0086] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to interchangeably. Each embodiment focuses on describing the differences from other embodiments. In the description of this specification, the terms "a preferred embodiment," "furthermore," "specifically," "in this embodiment," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the embodiments in this specification. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described can be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0087] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A high-velocity absolute femtosecond laser ranging device, characterized in that, The device includes a precision measurement light source system, a coarse measurement laser light source, a coarse-precision fusion ranging optical path, and a measurement signal detection and processing module. The precision measurement light source system is used to output a sampling clock signal and a repetition rate locked femtosecond laser precision measurement signal; The coarse measurement laser source is used to output a coarse measurement laser signal, wherein the femtosecond laser fine measurement signal and the coarse measurement laser signal have different wavelengths; The coarse-fine fusion ranging optical path is used to transmit the femtosecond laser fine measurement signal and the coarse measurement laser signal to the target under test, and the target under test reflects the signal to form the measurement optical signal and the coarse measurement optical signal, and acquire the reference optical signal; The measurement signal detection and processing module is used to perform coarse and fine measurement calculations on the reference optical signal, the measurement optical signal, and the coarse measurement optical signal to obtain the ranging result; wherein: The coarse-fine fusion ranging optical path includes an optical fiber interferometric path and an optical fiber collimator, wherein: The fiber optic interferometric optical path is used to perform signal measurement on the target under test based on fiber optic transmission, and to obtain a reference optical signal, a measurement optical signal and a coarse measurement optical signal. The fiber collimator is disposed between the exit of the fiber interference optical path and the target under test, and is used to convert the divergent light output from the fiber into parallel light, and also to couple the parallel light reflected by the target under test into the fiber. The fiber optic interferometric path includes a filter, a coupler, a first circulator, a second circulator, and a wavelength division multiplexer. The femtosecond laser precision measurement signal is split into two paths after passing through the filter and coupler: one path serves as a reference light directly input to the measurement signal detection and processing module; the other path serves as the measurement light, passing through the first circulator and the wavelength division multiplexer, then being converted into spatially collimated light by the fiber optic collimator and incident on the target. It then returns along the original path, passing through the wavelength division multiplexer and the first circulator sequentially to obtain the measurement light signal, which is then transmitted to the measurement signal detection and processing module. The coarse measurement laser source passes through the second circulator, is input to the wavelength division multiplexer, and combines with the measurement light signal. After passing through the fiber optic collimator, it is incident on the target and returns along the original path to the second circulator to obtain the coarse measurement light signal, which is also transmitted to the measurement signal detection and processing module.

2. The high-velocity absolute femtosecond laser ranging device according to claim 1, characterized in that, The precision measurement light source system includes a time and frequency reference module, a signal generation module, and a femtosecond laser light source, wherein: The time and frequency reference module is used to provide a standard frequency reference signal; The signal generation module outputs two standard frequency signals based on the standard frequency reference signal provided by the time-frequency reference module: one input is the repetition rate locking reference signal provided by the femtosecond laser source, and the other input is the frequency provided by the measurement signal detection and processing module. f s The sampling clock signal, The femtosecond laser source is used to emit a femtosecond laser precision measurement signal with repetition rate lock.

3. The high-velocity absolute femtosecond laser ranging device according to claim 2, characterized in that, The center wavelength of the filter is basically the same as the center wavelength of the femtosecond laser source, and the bandwidth range of the filter does not overlap with the bandwidth range of the coarse measurement laser source.

4. The high-velocity absolute femtosecond laser ranging device according to claim 3, characterized in that, The measurement signal detection and processing module includes first to third photodetectors, a high-speed signal acquisition circuit, and a signal processing circuit, wherein: The first to third photodetectors are used to receive the reference optical signal, the measurement optical signal and the coarse measurement optical signal output from the coarse and fine fusion ranging optical path, respectively, and convert them into corresponding electrical signals. The high-speed signal acquisition circuit is used to acquire clock signals. f s Let be the sampling frequency, and be the repetition frequency. The reference electrical signal and the measured electrical signal are sampled to generate a reference electrical pulse signal and a measured electrical pulse signal; The signal processing circuit is used to process the coarse measurement signal to obtain the coarse measurement result, process the reference electrical pulse signal and the measurement electrical pulse signal, and fuse the coarse measurement result to obtain the ranging result.

5. The high-velocity absolute femtosecond laser ranging device according to claim 1, characterized in that, The coarse measurement laser source uses a nanosecond laser to achieve low-precision measurement of the target based on the TOF method.

6. The high-velocity absolute femtosecond laser ranging device according to claim 4, characterized in that, Distance measurement results for: ； in, The group velocity of the light pulse in the air. For time delay, For the repetition rate of the femtosecond laser precision measurement signal, sampling frequency Repetition frequency of femtosecond laser precision measurement signal The frequency difference The period is an integer multiple of the non-fuzzy range.

7. The high-velocity absolute femtosecond laser ranging device according to claim 6, characterized in that, Integer multiples of the non-fuzzy range period The calculation formula is: ； In the formula, INT stands for floor function. This is a rough distance measurement.

8. The high-velocity absolute femtosecond laser ranging device according to claim 7, characterized in that, Coarse distance measurement The calculation formula is: ； in, c At the speed of light, To roughly measure the time difference from laser emission to reception.

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